| a. | 1. | Not in the regular, usual, or established form; not according to official, conventional, prescribed, or customary forms or rules; irregular; hence, without ceremony; |
| 2. | Deranged in mind; out of one's senses. |
| Adj. | 1. | informal - not formal; "conservative people unaccustomed to informal dress"; "an informal free-and-easy manner"; "an informal gathering of friends" Antonyms: formal - being in accord with established forms and conventions and requirements (as e.g. of formal dress); "pay one's formal respects"; "formal dress"; "a formal ball"; "the requirement was only formal and often ignored"; "a formal education" |
| 2. | informal - not officially recognized or controlled; "an informal agreement"; "a loose organization of the local farmers" Synonyms: loose | |
| 3. | informal - used of spoken and written language Antonyms: formal - (of spoken and written language) adhering to traditional standards of correctness and without casual, contracted, and colloquial forms; "the paper was written in formal English" | |
| 4. | informal - having or fostering a warm or friendly atmosphere; especially through smallness and informality; "had a cozy chat"; "a relaxed informal manner"; "an intimate cocktail lounge"; "the small room was cozy and intimate" |